The correct answer is A. i, ii, iii.
A ZigBee coordinator is a device that initiates and maintains the ZigBee network. It is the first device to join the network and is responsible for assigning addresses to other devices on the network.
A ZigBee router is a device that helps to route data between other devices on the network. It does this by storing information about the location of other devices on the network.
A ZigBee end device is a device that uses the ZigBee network to communicate with other devices. It does not have the ability to route data between other devices on the network.
A ZigBee accessor is a device that is used to connect to a ZigBee network. It does not have the ability to communicate with other devices on the network.